Specially formatted optical disk and method of playback

ABSTRACT

In an optical disk storing digital image information in the form of a succession of blocks, each comprising a plurality of frames comprising I-, P- and B-pictures, wherein an address format is preformatted in front of the block of image information of said plurality of frames, and the data arrangement within each image information blocks is such that I- and P-pictures are collectively disposed. The position of the I-pictures within each block is shifted from one block to another. The I-picture data may be divided into fraction according to the position on the screen, the DCT frequency, or layering, and the fractional I-picture data may be arranged in the image information blocks, and a header or parity signal is recorded in front of each fractional I-picture data. With such a configuration, it is possible to increase the speed of fast playback, and realize smooth playback picture.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an optical disk and a method ofplaying back from an optical disk.

[0002]FIG. 29 is a block diagram showing a conventional optical diskrecording/playback device shown in Japanese Patent Kokai Publication114369/1992. An A/D converter 1 converts a video signal, an audio signalor the like into digital information. An information compressing means 2serves to compress the output of the A/D converter 1. A frame sectorconverting means 3 converts the compressed information into sectorinformation equal in length to a multiple of the frame period. Anencoder 4 encodes the output of the frame sector converting means 3. Amodulator 5 modulates the output of the encoder 4 into predefinedmodulated codes so as to reduce interference between codes on therecording medium. A laser driver 6 is for modulating the laser light inaccordance with the modulated codes. A laser output switch 7 is drivenby the laser driver 6 to vary the current supplied to the laser in anoptical head 8, for emitting laser light.

[0003] An actuator 9 is for tracking the emitted light beam. A traverseor feed motor 10 is for moving the optical head 8 in the radialdirection of a disk 12 which can record information by magneto-opticalrecording or phase-change recording.

[0004] A disk motor 11 is driven by a motor driver 19 to rotate the disk12. The motor drivers 19 are controlled by first and second motorcontrollers 20. A playback amplifier 13 amplifies the playback signalfrom the optical head 8. A demodulator 14 demodulates the amplifiedplayback signal to obtain data from the recorded, modulated signal. Adecoder 15 decodes the demodulated signal, and a frame sector inverseconversion means 16 performs frame sector inverse conversion to restoreoriginal image data with the addresses and parities having been removed.An information expanding means 17 expands the compressed information,and a D/A converter 18 converts the expanded information into an analogvideo or audio signal.

[0005]FIG. 30 shows, in a simplified form, the data arrangementstructure (layer structure) of the Moving Picture Coding Experts Group(MPEG) system which is a standard method of transferring and storingcompressed digital moving picture information. In FIG. 30, reference 21denotes a group of pictures (hereinafter referred to as “GOPs”)consisting of information of a plurality of frames, 22 denotes a GOPlayer formed of several pictures (screens), 23 denotes slices into whicheach picture is divided, 24 denotes a slice layer formed of severalmacroblocks, 25 denotes a microblock layer, and 26 denotes a block layerformed of 8×8 pixels.

[0006] The microblock layer 25 is a block consisting of 8×8 pixels,which is the minimum unit of encoding in the MPEG system, and discretecosine transform (hereinafter referred to as “DCT”) is effected takingeach micro block as a unit. Four adjacent Y signal blocks and one Cbblock and one Cr block which correspond, with regard to position, to thefour Y signal blocks, i.e., six blocks in all form a macroblock 24.Several macroblocks 24 form a slice 23 The macroblock 24 is a minimumunit for motion compensated prediction, and the motion vector for themotion compensated prediction are determined taking each macroblock 24as a unit.

[0007]FIG. 31 a diagram showing the conventional encoding structure forthe case where 17 pictures form one GOP. In FIG. 3127 denotes anI-picture which is image information for which intra-frame DCT iseffected, 29 denotes a P-picture which is image information for whichforward motion-compensated DCT encoding is effected using the I-pictureor another P-picture (P-picture other than the P-picture for which theforward motion-compensated DCT encoding is being effected) as areference picture, 28 denotes a B-picture for which motion compensatedDCT encoding is effected using the I-picture and/or P-pictures atpreceding and succeeding positions, as reference pictures.

[0008]FIG. 32 is a diagram showing the conventional encoding structurefor the case where 10 pictures form one GOP, and FIG. 33 is a diagramshowing the conventional encoding structure for the case where 15pictures form one GOP.

[0009] In the drawings, P-, B- and I-pictures are respectivelyrepresented as “P” or “P-picture,” “B” or “B-picture,” and “I” or“I-picture.”

[0010] The operation will next be described with reference to thedrawings. With the advancement in the digital image informationcompression technology, it is now possible to realize an image filingsystem which is very convenient to use, by recording the compressedinformation on a disk, with which search is much easier than having aVTR with a magnetic tape. Since, such disk file system handles digitalinformation, there is no deterioration due to dubbing, and becauserecording and reproduction is achieved optically and there is no directcontact with the recording medium, reliability is high.

[0011] Conventionally, an optical disk recorder shown in FIG. 29 is usedfor recording the digital compressed motion information of the MPEGsystem shown in FIG. 30. The image information digitized by the A/Dconverter 1 is converted at the information compression means 2 intoinformation of a standard compression picture system such as an MPEGsystem. The compressed information is encoded and modulated so that theeffects of the interference between the codes on the disk is reduced,and is then recorded on a disk 12. By making the amount of data for eachGOP substantially identical, and by dividing information into sectorshaving a length equal to a multiple of a frame period, editing and thelike, treating each GOP as a unit, is possible.

[0012] During playback, the image information reproduced from theoptical disk 12 is amplified by the playback amplifier 13, and returnedinto a digital data by the demodulator 14 and the decoder, and theoriginal image data with the addresses and parities having been removedcan be restored at the frame sector inverse conversion means 16.Furthermore, an image signal is restored by effecting, MPEG decoding,for example, at the information expanding means 17, and is thenconverted into an analog signal by the D/A converter 18 so that displayon a monitor or the like is possible.

[0013] If the MPEG system is used as the digital motion compressionmethod as described above, the encoding structure comprising one or morecompressed I-pictures 27 by means of intra-frame DCT, one or moreP-pictures 29 which is formed of image information obtained by DCTencoding with motion compensation in the forward direction, and one ormore B pictures 28 obtained by DCT encoding with motion compensationusing I- and/or P-pictures positioned in front and at the back along thetime axis, as reference pictures, as shown in FIG. 31 to FIG. 33.

[0014] Because an I-picture is obtained by intra-frame DCT, is possibleto effect reproduction of the image with an I-picture independently. AP-picture, on the other hand, is obtained by forward motion compensationand the reproduction of the image with a P-picture is not effected untilafter the reproduction of the I-picture. Because the B-picture isobtained by prediction from both sides, both the I- and/or P-picturesmust first be reproduced before the B-picture. The amount of data is thesmallest and the efficiency of encoding is the best with the B-picture,because it is predicted in both directions.

[0015] Because the B-picture is not reproduced independently, itrequires an I- or P-pictures, so that if the number of the B-pictures isincreased, the capacity of the buffer memories must be increased, andthe delay time from the data input to the image playback is lengthened.In a storage media, represented by optical disks or the like, anencoding method with a high compression efficiency is desired forlong-time recording and the delay in the image playback is notproblematical. Accordingly, the encoding system showing in FIG. 31 toFIG. 33 is appropriate for simple playback.

[0016] Now let us consider how the conventional image search and fastplayback are effected from a disk receding data with the encodingstructure as described above. If the encoding structure is as shown inFIG. 33, and if playback is made by extracting I-pictures, fast playbackis possible. In this case, when an I-picture is reproduced, then a trackjump is conducted to access the next or preceding GOP, and the I-picturetherein is reproduced. By repeating such an operation, a fast forward orreverse playback is realized. The feed speed for fast forward or reverseplayback is limited to the 15-time speed in case of FIG. 33, and10-times in the case of FIG. 32.

[0017] In the actual image search, if the speed is too high, it isdifficult for the human eyes to recognize the image. For roughrecognition, the fast search at a 10-time or more speed is appropriate,but for search with regard to the details after the rough search, fastplayback or reverse playback at several-time speed is necessary It istherefore necessary that special playback can be conducted over a widerange, of from several tens to several times the normal playback speed,to permit effective image search. Where the compressed data of the MPEGsystem is used, and if it is attempted to reproduce P-pictures in theencoding structure of FIG. 31 to FIG. 33, the B-pictures positionedbefore the P-pictures are also read, and it is therefore difficult torealize four to eight time speed.

[0018] Since the conventional playback method reproduce the encodingstructure on-the disk as it is, special playback can be achieved only byI-pictures, and fast forward and reverse playback can be achieved onlyat a speed which corresponds to the number of frames contained in oneGOP or a multiple thereof.

[0019] Also, with the recording format of the digital image shown inconnection with the prior art examples, I-pictures, P-pictures andB-pictures are arranged in a sequence along the time axis, so that thespecial playback is limited to the following method.

[0020] Particularly, a fundamental method for special playback in thesystem for recording digital motion picture image in the prior artperforms special playback using information recorded in the TOC areawhich is at the inner periphery of the disk. In this case, specialplayback is achieved by reading, in accordance with the head address ofthe scene change (the address of a location where a picture immediatelyafter the scene change is recorded) or the head address of the imagefile recorded in the TOC area, the digital motion picture image of theI-picture stored at the address, and reproducing them in turn.

[0021] The conventional operation for reading from the optical disk insuch a method is shown in the flowchart of FIG. 34. This flowchart showsthe case in which special playback is effected on the basis of theaddress at the head of the scene in the motion picture image informationrecorded in the TOC area. First, a jump is made to the TOC area, and thescene head address is stored in the internal memory, and then jump ismade to the address that has been stored, and the I-picture in the GOPto which jump has been made is reproduced, and displayed, and movementto the next address of jump destination is made. Such a sequence ofoperation is repeated.

[0022] With such a conventional method, however, a large amount ofaddresses which should be searched for (and to which a jump is destined)need to be stored, and the TOC information must be rewritten each time arecording is made.

[0023] Moreover, during special playback in the conventional system, itis necessary to skip B-picture data for reproducing P-pictures, but asthe I-pictures, B-pictures and P-pictures are recorded on the disk insequence, waiting time may have to be spent before reproducing aP-picture when a track jump is conducted.

[0024] Furthermore, in the conventional system the amount of data of theI-picture encoded by intra frame DCT is larger than the amount of dataof P- or B-pictures, so that super-fast playback, of several tens timesthe normal playback speed cannot be realized because the time forinputting data may be insufficient.

[0025] When starting a search in the conventional system for a desiredGOP from an arbitrary position on the disk, the search operation must berepeated several times for finding the head of each GOP (at which timecode or address of the image is recorded).

[0026] Furthermore, as the scene change position in the motion pictureimage information is not known, a scene-by-scene search for finding ascene cannot be achieved by using the conventional system.

[0027] In addition, because only part of the data in each GOP is read inthe special playback, image playback may not be accomplished, orplayback may be possible only with regard to part of the display screenin the conventional system.

SUMMARY OF THE INVENTION

[0028] An object of the invention is to increase the special playbackspeed.

[0029] Another object of the invention is to reduce rotation waitingtime when a track jump is performed.

[0030] Another object of the invention is to enable continuousreproduction of I-pictures.

[0031] Another object of the invention is to reduce the capacity ofmemory for storing images during playback.

[0032] Another object of the invention is to facilitate locating thehead position of each GOP.

[0033] Another object of the invention is to enable recording ofinformation designating the manner of playback.

[0034] According to an aspect of the invention, there is provided anoptical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an I-picture obtained by intra-frame DCT encoding, P-picture data ofone or more P-pictures obtained by DCT encoding with forward motioncompensation, and B-picture data of B-pictures obtained by DCT encodingwith motion compensation using the data of the I- and/or P-picturespositioned in front and at the back thereof as reference pictures,

[0035] wherein an address format is preformatted in front of the blockof image information of said plurality of frames, and the dataarrangement within each image information blocks is such that I- andP-pictures are collectively disposed.

[0036] Since the I- and P-picture data are collectively disposed, thatis, the I- and P-picture data within each GOP are disposed insuccession, they are read in succession during normal playback arestored in a buffer memory, and then decoded, and B-picture data arethereafter read and decoded sequentially to restore image data withinthe GOP. The capacity of the buffer memory can be reduced. Duringspecial replay, only I-picture data are read and decoded, while trackjump can be effected at the position where the P- or B-picture data isrecorded. During special replay, the time for reproducing P- andB-picture data can be omitted, so that the special playback speed can beincreased.

[0037] It may be so arranged that a parity signal or header signal forrecognition is recorded at the head of the I-picture data.

[0038] With the above configuration, the position detection of the I-and P-picture data and discrimination between the I- and P-picture dataduring fast playback can be made with ease, and continuous reproductionof I-picture data is achieved without reproducing the management data atthe head of the GOP at the time of track jump.

[0039] It may be so arranged that the order of data arrangement of theI- and P-picture data within each of the image information blocks isdifferent from one image information block to another image informationblock.

[0040] The configuration in which the order of data arrangement of theI- and P-picture data within each of the image information blocks isdifferent from one image information block to another image informationblock can be implemented by exchanging the positions of the I- andP-picture data between adjacent image information blocks. With the aboveconfiguration, rotation waiting time at the time of track jump can bereduced.

[0041] It may be so arranged that the I- and P-picture data within eachimage information block are disposed adjacent to each other, and theorder of data arrangement of the

[0042] I-, P- and B-picture data is different from one image informationblock to another image information block.

[0043] The configuration in which the order of data arrangement of theI-, P- and B-picture data is different from one image information blockto another image information block can be implemented by exchanging thepositions of the I-, P- and B-picture data between adjacent imageinformation blocks. With the above configuration, the rotation waitingtime at the time of track jump can be further reduced.

[0044] It may be so arranged that the area within the optical disk isdivided into a plurality of zones for respective radius ranges, thescanning linear velocities in different zones being substantially equalto each other, address data and a header signal being preformatted atthe head of each of the image information blocks, and the number of databits for each of the image information blocks being identical betweenthe image information blocks, and the data recording bit length of theimage information block within each sector being a multiple of thecircumferential length of the track on the disk.

[0045] That data recording bit length of the image information blockwithin each sector being a multiple of the circumferential length of thetrack on the disk means the recording capacity per image informationblock (GOP) is a multiple of the recording capacity per revolution. Withthe above configuration, the variation in the linear velocity can berestrained within a sufficient range, and the GOP head positions can berecognized with ease wherever position on the disk is being scanned.

[0046] It may so arranged that a mirror-surface part for track offsetdetection is provided for each of the image information blocks.

[0047] With the above configuration, it is possible to recognize the GOPhead positions by reference to the mirror-surface parts, and by settingthe length of the mirror-surface part to be different from other parts,the GOP head positions can be recognized from the sum signal at theoptical head, without reproducing the data.

[0048] According to another aspect of the invention, there is providedan optical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an I-picture obtained by intra-frame DCT encoding, P-picture data ofone or more P-pictures obtained by DCT encoding with forward motioncompensation, and B-picture data of B-pictures obtained by DCT encodingwith motion compensation using the data of the I- and/or P-picturespositioned in front and at the back thereof as reference pictures,

[0049] wherein an address data preformatted in front of the respectiveimage information blocks (or image files) are aligned on a straight lineextending in the radial direction.

[0050] With the above configuration, wherever the light spot is tracing,the head position of each GOP can be recognized, and the track jumpstarting point can be defined accordingly

[0051] According to another aspect of the invention, there is providedan optical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an I-picture obtained by intra-frame DCT encoding, P-picture data ofone or more P-pictures obtained by DCT encoding with forward motioncompensation, and B-picture data of B-pictures obtained by DCT encodingwith motion compensation using the data of the I- and/or P-picturespositioned in front and at the back thereof as reference pictures,

[0052] wherein a jump destination address for special playback isrecorded in the attribute data recording area at the head of each of theimage information blocks.

[0053] With the above configuration, special playback can be conductedin any of different modes depending on the contents of the motionpicture, and the manner of special playback can be designated duringrecording, and by repeating the track jump using the above information,special playback in which motion picture scene is completed orcontinuous reproduction of only the scene head portions can be achieved.

[0054] According to another aspect of the invention, there is providedan optical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an T-picture obtained by intra-frame DCT encoding, P-picture data ofone or more P-pictures obtained by DCT encoding with forward motioncompensation, and B-picture data of B-pictures obtained by DCT encodingwith motion compensation using the data of the I- and/or P-picturespositioned in front and at the back thereof as reference pictures,

[0055] wherein presence/absence of scene change detected from thetemporal change in the luminance or chrominance information of the imageis recorded in the attribute data recording area at the head of each ofthe image information blocks.

[0056] With the above configuration, it is possible to conduct imagesearch by sequentially reproducing the still pictures immediatelysucceeding or immediately preceding the scene changes, and it ispossible to conduct editing taking each scene (partitioned by the scenechanges) as a unit, i.e., on a scene-by-scene basis.

[0057] According to another aspect of the invention, there is provided amethod of playing back an optical disk recording digital imageinformation in the form of a succession of image information blocks,each comprising I-picture data of an I-picture obtained by intra-frameDCT encoding, P-picture data of one or more P-pictures obtained by DCTencoding with forward motion compensation, and B-picture data ofB-pictures obtained by DCT encoding with motion compensation using saidI- and/or P-pictures positioned in front and at the back thereof asreference pictures,

[0058] wherein presence/absence of scene change detected from thetemporal change in the luminance or chrominance information of the imageis recorded in the attribute data recording area at the head of each ofthe image information blocks.

[0059] With the above configuration, it is possible to conduct imagesearch by sequentially reproducing the still pictures immediatelysucceeding or immediately preceding the scene changes, and it ispossible to conduct editing taking each scene (partitioned by the scenechanges) as a unit, i.e., on a scene-by-scene basis.

[0060] According to another aspect of the invention, there is provided amethod of playing back an optical disk recording digital imageinformation in the form of a succession of image information blocks,each comprising I-picture data of an I-picture obtained by intra-frameDCT encoding, P-picture data of one or more P-pictures obtained by DCTencoding with forward motion compensation, and B-picture data ofB-pictures obtained by DCT encoding with motion compensation using saidI- and/or P-pictures positioned in front and at the back thereof asreference pictures,

[0061] said method comprising the steps of:

[0062] using an optical head having a coarse actuator for accessing to adesired position, and a fine actuator for jumping to a desired track atthe inner or outer periphery of the optical disk;

[0063] playing back the I-picture data through search and identificationby reference to the parity signal or the header signal within the imageinformation block on the optical disk;

[0064] reproducing the I-picture data in the next image informationblock; and

[0065] repeating the above operations to perform fast playback orreverse playback.

[0066] With the above method, it is possible to reproduce I-pictures ofthe respective GOPs, by repeating track jump by referring to the parityor header signal at the head of each of the I-pictures.

[0067] According to another aspect of the invention, there is provided amethod of playing back an optical disk recording digital imageinformation in the form of a succession of image information blocks,each comprising I-picture data of an I-picture obtained by intra-frameDCT encoding, P-picture data of one or more P-pictures obtained by DCTencoding with forward motion compensation, and B-picture data ofB-pictures obtained by DCT encoding with motion compensation using saidI- and/or P-pictures positioned in front and at the back thereof asreference pictures,

[0068] said method comprising the steps of:

[0069] using an optical head having a coarse actuator for accessing to adesired position, and a fine actuator for jumping to a desired track atthe inner or outer periphery of the optical disk;

[0070] playing back the I-picture data through search and identificationby reference to the parity signal or the header signal within the imageinformation block on the optical disk;

[0071] then playing back the P-picture data of a plurality of P-picturessuccessively;

[0072] conducting a track jump;

[0073] reproducing the I-picture data in the next image informationblock;

[0074] then playing back the P-picture data of a plurality of P-picturessuccessively; and

[0075] repeating the above operations to perform fast playback orreverse playback.

[0076] With the above method, the playback speed is improved.

[0077] According to another aspect of the invention, there is provided amethod of playing back an optical disk wherein the rotational speed ofthe optical disk during fast playback or reverse playback of motionpicture image is higher than the rotational speed of the optical diskduring normal playback.

[0078] With the above method, the data transfer rate is improved.

[0079] According to another aspect of the invention, there is provided amethod of playing back an optical disk wherein the rotational speed ofthe optical disk is raised in the region in which no data which need tobe read during fast playback or reverse playback of a motion pictureimage is recorded, and is lowered to the linear velocity at whichreproduction of data is possible, in the region in which I- andP-picture data is recorded.

[0080] With the above method, the overall playback speed is improved. Itis also possible to achieve smooth fast special playback of motionpicture image without using track jump.

[0081] According to another aspect of the invention, there is providedan optical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an I-picture obtained by intra-frame DCT encoding, P-picture data ofone or more P-pictures obtained by DCT encoding with forward motioncompensation, and B-picture data of B-pictures obtained by DCT encodingwith motion compensation using the data of the I- and/or P-picturespositioned in front and at the back thereof as reference pictures,

[0082] wherein said I-picture data is divided into fractional I-picturedata for a plurality of regions into which a display screen is divided,and the fractional I-picture data are arranged in said image informationblock, and a header or parity signal is recorded in front of eachfractional I-picture data.

[0083] It may additionally be so arranged that the fractional I-picturedata in the adjacent image information blocks in the adjacent recordingtracks may be different.

[0084] With the above configuration, through search for a header signalor parity signal recorded in front of the screen fractional I-picturedata, the screen fractional I-picture data can be sequentiallyreproduced.

[0085] The header or parity signal is recorded at the head of the dataobtained by dividing I-picture data for the respective regions in thescreen, so that when conducting a special playback in which onlyI-pictures in the respective GOPs are reproduced and joined, it is notnecessary to read all the I-picture data. Accordingly, the specialplayback speed multiplier is increased, and it is possible to obtainsmooth continuous movement in the picture during the special playback.

[0086] According to another aspect of the invention, there is providedan optical disk in which DCT-encoded I-picture data is allocated into aplurality of sub-blocks according to the horizontal and verticalfrequencies, from the DC components to the high-frequency components,sub-blocks of I-, P- and B-picture data in the adjacent imageinformation blocks in the adjacent tracks are disposed with their orderbeing altered, and a header or parity signal indicating which of thefrequency components the content of each sub-block is for is recorded infront of each sub-block.

[0087] With the above configuration, the frequency-divided I-picturedata of a desired low-frequency component can be arbitrarily accessedand sequentially reproduced by searching for the header or paritysignal. As a result, is not necessary to read all the I-picture data ifthe resolution of the displayed picture may be sacrificed to a certainextent, and special playback speed multiplier is high and yet smoothlymoving picture can be produced. Moreover, when zone CAV format disk isused, the rotation waiting time during special playback is reduced.

[0088] According to another aspect of the invention, there is providedan optical disk, in which DCT-encoded I-picture data is allocated into aplurality of sub-blocks according to the horizontal and verticalfrequencies, from the DC components to the high-frequency components,the frequency-divided I-picture data within the adjacent imageinformation blocks in the adjacent tracks are disposed differently, anda header or parity signal indicating which of the frequency componentsthe content of each sub-block is for is recorded in front of eachsub-block.

[0089] With the above configuration, it is possible to achievehigh-speed fast playback or reverse playback of frequency-dividedI-picture data by repeating track jump through search for the headersignal or parity signal. That is, the frequency-divided I-picture dataof a desired low-frequency component can be arbitrarily accessed andsequentially reproduced by searching for the header signal or paritysignal. As a result, it is not necessary to read all the I-picture dataif the resolution of the displayed picture may be sacrificed to acertain extent, and the special playback speed multiplier is high andyet smoothly moving picture can be displayed. Moreover, when zone CAVformat disk is used, the rotation waiting time during special playbackis reduced.

[0090] According to another aspect of the invention, there is providedan optical disk storing digital image information in the form of asuccession of blocks, each comprising a plurality of frames comprising,in mixture, I-picture data forming image information obtained byintra-frame DCT encoding, P-picture data obtained by DCT encoding withforward motion compensation, and B-picture data obtained by DCT encodingwith motion compensation using said I- and/or P-picture data positionedin front and at the back thereof as references,

[0091] wherein the digital motion picture image information is dividedinto lower-layer data having smaller numbers of pixels and lines, andupper-layer data which produce, in combination with the lower-layerdata, an image with larger numbers of pixels and lines, and a header orparity signal for indicating the type of the data block is recorded infront of each data block.

[0092] It may additionally be so arranged that the lower-layer data andthe upper-layer data are disposed, with their order being altered.

[0093] With the above arrangement, the digital motion picture imageinformation can be sequentially reproduced through search for the headeror parity signal and arbitrarily accessing I-picture data of desired,small numbers of pixels and lines. Moreover, it is not necessary to readall the I-picture data during special playback and yet image can bereproduced, and it is therefore possible to increase the specialplayback speed multiplier.

[0094] It may be so arranged that the order of data arrangement of I-,P- and B-picture data within an image information block is differentbetween adjacent image information blocks.

[0095] With the above configuration, it is possible to achievehigh-speed fast playback or reverse playback of screen-divided I-picturedata by repeating track jump through search for the header or paritysignal recorded in front of each data.

[0096] It may be so arranged that identification signal indicatingwhether the I-picture data is a screen-divided data, a frequency-divideddata, or data divided by the numbers of pixels and lines is written atthe head of each image information block.

[0097] With the above configuration, it is possible to identify whetherthe recorded digital motion picture image information is of an I-picturedata, frequency-divided data, screen-region-divided data, orpixel/line-number divided data by finding an identification signalwritten at the head of each image information block and identifying thecontent thereof, and it is possible to sequentially reproduce therecorded digital motion picture image information.

[0098] It may be so arranged that the head positions of the digitalimage information blocks are aligned in the radial direction of theoptical disk.

[0099] With the above configuration, it is possible to accuratelydetermine the timings of the track jump, and to continuously readspecial playback data without rotation waiting time.

[0100] According to another aspect of the invention, there is provided amethod of playing back from an optical disk comprising the steps of:

[0101] using an optical disk playback device comprising a trackingactuator for tracking a scanning spot on a predefined track, a trackingcontrol circuit, and a track jump circuit for performing jumpingscanning,

[0102] using an optical disk according to the descriptions above, and

[0103] repeating jumping operation on the basis of a header or paritysignal recorded in front of each I-picture data to perform high-speedplayback or reverse playback.

[0104] With the above method, it is thereby possible to performhigh-speed playback or reverse playback of divided digital imageinformation.

[0105] According to another aspect of the invention, there is provided amethod of playing back from an optical disk, comprising the steps of:

[0106] using an optical disk playback device comprising a trackingactuator for tracking a scanning spot on a predefined track, a trackingcontrol circuit, and a track jump circuit for performing jumpingscanning,

[0107] using an optical disk according to the descriptions above, and

[0108] repeating jumping operation on the basis of an identificationsignal written at the head of each image information block to performhigh-speed playback or reverse playback.

[0109] With the above method, it is possible to identify the type of thedata of each image information block on the basis of an identificationsignal written at the head of each image information block, so that thedigital image information can be reproduced.

[0110] Further scope of applicability of the present invention willbecome apparent from the detailed description given hereinafter.However, it should be understood that the detailed description andspecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

[0111] The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

[0112]FIG. 1 is a block diagram showing the recording system inEmbodiment 1;

[0113]FIG. 2A and FIG. 2B are diagrams showing the digital motionpicture image data recording format in Embodiment 1;

[0114]FIG. 3A and FIG. 3B are diagrams showing the variation of the diskrotational speed during fast playback of the image data in Embodiment 1;

[0115]FIG. 4 is a flowchart showing the operation of the specialplayback on the basis of the jump destination address written in thevideo attribute data in Embodiment 1;

[0116]FIG. 5 is a flowchart showing the operation of data reading fromthe optical disk during special playback in Embodiment 1;

[0117]FIG. 6 is a flowchart showing the operation of reading data fromthe optical disk in special playback for continuously reproducing I- andP-pictures in Embodiment 1;

[0118]FIG. 7A to FIG. 7C are diagrams showing the digital image datarecording format in Embodiment 2;

[0119]FIG. 8 is a diagram showing the digital image data recordingformat in Embodiment 2;

[0120]FIG. 9 is a diagram showing the digital image data recordingformat in Embodiment 3;

[0121]FIG. 10 is a diagram showing the digital image data recordingformat on the disk in the continuous guide groove system in Embodiment3;

[0122]FIG. 11 is a diagram showing the digital image data recordingformat on the disk in the sample-servo system in Embodiment 3;

[0123]FIG. 12 is a flowchart showing the reading operation of Embodiment3, in which the disk rotation speed is raised during special fastplayback;

[0124]FIG. 13A and FIG. 13B show the arrangement of data in a GOP ofdigital motion picture image data, and the overall data arrangementincluding audio data;

[0125]FIG. 14 shows data arrangement of digital motion picture imagedata recorded on an optical disk in Embodiment 4:

[0126]FIG. 15 is a block diagram showing a digital motion picture imageinformation recording device using an optical disk of Embodiment 4;

[0127]FIG. 16 shows data arrangement of screen-divided I-picture data ina GOP in Embodiment 4;

[0128]FIG. 17 is a flowchart showing the operation of Embodiment 4;

[0129]FIG. 18A shows frequency-divided I-picture data arrangement in aGOP of Embodiment 5, and the paths of track jump during playback;

[0130]FIG. 18B shows how the frequency divide I-picture data isobtained;

[0131]FIG. 19 shows frequency-divided I-picture data arrangement in aGOP of another example of configuration of Embodiment 5, and the pathsof track jump during playback;

[0132]FIG. 20 shows frequency-divided I-picture data arrangement in aGOP of another example of configuration of Embodiment 5, and the pathsof track jump during playback;

[0133]FIG. 21 shows frequency-divided I-picture data arrangement in aGOP of another example of configuration of Embodiment 5, and the pathsof track jump during playback;

[0134]FIG. 22 is a flowchart showing the operation of Embodiment 5;

[0135]FIG. 23 shows data arrangement on an optical disk of the zone CAVtype of Embodiment 5, which is preformatted in a sample-servo method;

[0136]FIG. 24 shows data arrangement on an optical disk of thecontinuous groove type of Embodiment 5;

[0137]FIG. 25 is a block diagram showing an example of circuit forrestoring image from the layered data of Embodiment 6;

[0138]FIG. 26 is a block diagram of a digital motion picture imageinformation playback circuit of Embodiment 6;

[0139]FIG. 27 shows data arrangement of I- and P-pictures in layeredform according to the numbers of pixels and lines on the optical diskaccording to Embodiment 6;

[0140]FIG. 28 shows data arrangement, with-only I-pictures having beenlayered, on the optical disk according to Embodiment 6;

[0141]FIG. 29 is a block diagram showing the conventional optical diskrecording and playback apparatus;

[0142]FIG. 30 is a diagram showing the data arrangement in MPEG system;

[0143]FIG. 31 is a diagram showing the code structure in which one GOPis formed of 17 pictures;

[0144]FIG. 32 is a diagram showing the code structure in which one GOPis formed of 10 pictures;

[0145]FIG. 33 is a diagram showing the code structure in which one GOPis formed of 15 pictures; and

[0146]FIG. 34 is a flowchart showing the operation during specialplayback conducted on the basis of the address stored at the head ofscene in digital motion picture image information stored in theconventional recording format, in the TOC area at the inner periphery ofthe disk.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0147] Embodiment 1

[0148]FIG. 1 is a block diagram showing a recording system of an opticaldisk device of Embodiment 1 of the present invention. In the drawing, anA/D converter 30 converts an analog video signal into a digital signal.A motion detector 31 detects the motion vector of the digital videosignal. A discrete cosine transform circuit 32 divides the imageinformation into horizontal and vertical spatial frequency components.Reference numeral 33 denotes an adaptive quantizer, and 34 denotes aninverse quantizer. An inverse discrete cosine transform circuit 35restores the image information from the frequency components. A framememory 36 stores the image information as reference images, on the basisof the motion vector, 37 denotes a variable-length encoder, and 38denotes a buffer memory. A format encoder 38 appends the addressinformation and attribute data.

[0149] A chrominance information comparator 40 compares the chrominanceinformation of a picture with chrominance information of precedingand/or succeeding picture, and in particular compares the chrominancecomponents of each picture with chrominance components of precedingand/or succeeding picture, used as a reference picture, after motioncompensation by motion vector detection. A luminance informationcomparator 41 compares luminance information of each picture withluminance information of the preceding and/or succeeding picture. Ascene change judging circuit 42 judges whether or not a scene change ispresent on the basis of the outputs of the comparators 40 and 41. Themembers 40, 41 and 42 form a scene change detector 100.

[0150] A modulating circuit 43 serves to restrain the effect of theinterference between codes, a laser modulating circuit 44 is formodulating the laser on the basis of the information from the modulatingcircuit 43. A servo circuit 45 performs focus tracking, feed control,and disk motor control. Reference numeral 46 denotes a systemcontroller.

[0151]FIG. 2A and FIG. 2B show the recording format of digital motionpicture image data in Embodiment 1. In FIG. 2A, reference numeral 47denotes wobble pits in a sample servo format or a mirror surface partfor track offset correction in a continuous groove system, andcorresponds to the wobble pits preformatted in the optical disk shown inFIG. 11 or a mirror surface part provided in the continuous groove shownin FIG. 10, 48 denotes a zone address for indicating the address in thedisk of a constant angular velocity (CAV) system, 49 denotes a headerindicating the head of the video GOP and a video GOP address indicatingthe address of the GOP, 50 denotes a video attribute data for recordingthe attribute data of the video signal, 51 denotes an I-picture headerindicating the head of an I-picture, and 52 denotes a video headerformed of the areas 49 to 51. Reference numeral 53 denotes an I-picture,54 denotes a second I-picture data separated by servo pits or a mirrorsurface 47, and 55 denotes a third I-picture data separated in the samemanner as the second I-picture data 54. Reference numeral 56 denotes aP-picture header, and 57 and 58 denote P1-picture data separated in thesame manner as the second I-picture data 54.

[0152]FIG. 2B shows the details of the format recorded in the videoattribute data 50. Reference numeral 59 denotes a scalability mode (typeof the hierarchy) of the digital image data arrangement, 60 denotes thenumber of frames in the GOP, 61 denotes the structure within the GOPdefining the arrangement of I-, B- and P-pictures within the GOP, 62denotes the structure of arrangement and position of the data within theI-picture, 63 denotes attribute data indicating whether the image withinthe GOP involves panning, zooming or scene change, 64 denotes a timecode of a video area formed of a plurality of GOPs, 65 denotes anaddress of destination of jump during special playback, 66 denotes anaudio mode, and 67 denotes a still-picture mode, 68 denotes a sparearea.

[0153]FIG. 3A and FIG. 3B show how the disk rotation speed is varied forfast playback of the image data recorded in the format of FIG. 2A andFIG. 2B.

[0154]FIG. 4 is a flowchart showing the operation for the specialplayback using the jump destination address for the special playbackwritten in the video attribute data area 50 at the head of the videoGOP. FIG. 5 is a flowchart showing the operation for the specialplayback using the data indicating whether a scene change is present ornot, written in the video attribute data area at the head of the videoGOP. FIG. 6 is a flowchart showing the operation for the specialplayback using in which only the I- and P-pictures within the GOP arereproduced.

[0155] The operation of Embodiment 1 will next be described withreference to the drawings. The video signal represented by those of theMPEG system, is recorded on disk 12 after having been digital-videoencoded. The analog video signal is first converted into digital data atthe A/D converter 30, and a motion vector is then detected at the motionvector detector 31. Three-dimensional compression is effected bycomparison with a reference image, discrete cosine transformation iseffected in the frequency directions (two-dimensional directions) at theDCT circuit 32, quantization is effected at the adaptive quantizer 33,and variable-length encoding is effected by the variable length encoder37.

[0156] The compressed digital motion picture information thus obtainedis passed through the buffer memory 38 and the format encoder 39 whereaddress, header, attribute data and the like are added, to be therebygive a format suitable for recording on the optical disk 12. Judgment onscene change is made by the use of the scene change detector 100connected to the output of the DCT circuit 35 for comparing successiveframes, or by the use of the motion vector detector 31 for detecting arapid change in the image.

[0157] In particular, an accurate judgment on the scenes can be made atthe scene change judging circuit 42 by comparing chrominance informationand luminance information separately along the time axis, at thechrominance information comparator 40 and the luminance informationcomparator 41, and by comparing the amount of variation and variationspeed for each picture.

[0158] The output of the scene change judging circuit 42 is stored asthe presence or absence of a scene change in the video attribute data 50in FIG. 2A and FIG. 2B In the format of FIG. 2A, the video attributedata 50 can be used to record, in addition to the presence or absence ofa scene change, the address of the jump destination at 65, the structureof the GOP at 61 and the number of pictures within the GOP at 60, thescalability mode at 59, the time code at 64 and the like, and specialplayback or the like can be effected using such attribute data.

[0159]FIG. 2A and FIG. 2B show the digital motion picture image datarecording format, in which I- and P-pictures are adjacent to each other,and video attribute data 50 is disposed at the head of the GOP. At thetime of recording, on the basis of the result of the judgment at thescene change judging circuit 42, the presence or absence of a scenechange is stored in the video attribute data 50 in FIG. 2A, and theaddress of a jump destination during special playback is also stored inthe video attribute data 50 at 65. Since the digital motion pictureimage recording circuit is provided with a buffer memory 38, therecording data is still held in the buffer memory 38 while the image isprocessed, so that the jump destination address can be stored.

[0160] For instance, when the GOP is of such an image which does notrequire jump playback (e.g., it consists of a succession of rapidlymoving images, or still-picture-like image which is similar to thepreceding GOP), information that the GOP need not be played back andshould be skipped over is stored in the attribute data, and if the nextGOP needs to be played back, a flag to that effect is set. The specialplayback is achieved by reproducing only the video attribute data 50 insequence, and playing back the GOPs for which this flag at the headthereof is set.

[0161] Instead of the flag, designation of the jump destination addressmay be used in 65.

[0162] In the case of the reverse playback, the buffer memory 38 neednot have a large capacity, and yet storage of the jump destinationaddress and setting of the flag indicating whether the preceding GOPneeds playback can be realized with ease.

[0163] The operation of reading from the optical disk is as shown inFIG. 5. First, the address of the head of the GOP is detected, and thenthe video attribute data 50 is read, an I-picture of the GOP isreproduced if a scene change is present, and jump is made to a next GOPif no scene change is present. In this way, the special playback iscontinued.

[0164] As shown in the flowchart of FIG. 4, special playback is alsopossible by reading the jump destination address stored in the videoattribute data 50. In this case, by reading the video attribute data 50,the jump destination address is stored, and, on the basis thereof, anI-picture is reproduced, and a track jump is also conducted when thecurrent GOP should be skipped over. In this way, the special playback isachieved.

[0165] By the use of the above methods, it is possible to achievespecial playback in which only such GOPs of a plurality of GOPs formedon the disk that need to be reproduced are reproduced in turn. In thesecases, still pictures are successively reproduced or still pictures atthe heads of respective scenes are continuously reproduced.

[0166] In a special playback in which I- and P-pictures are continuouslyreproduced, the operation is as shown in FIG. 6. In this case, after thevideo header 52 is detected, I- and P-pictures are read, and when aB-picture header is detected, a track jump is conducted to the videohead of the next GOP and similar operation is repeated in the successiveGOPs. However, with this method, the special playback speed multiplier(the ratio of the time for normal replay to the time for fast replay) islimited because the amount of data for I- and P-pictures in each GOP islarge.

[0167] Embodiment 2

[0168] Embodiment 2 is next described with reference to the drawings.FIG. 7A shows the method of reading data in which the image datarecorded in the format of FIG. 2A is fast-played back by track jump, andFIG. 7B shows the disposition of the video headers 52 on the disk, andFIG. 7C shows the track jump at the video header 52.

[0169] In FIG. 8, the order of I- and P-pictures is reversed at everytrack-adjacent GOP, so that I-picture reproduction at the time of trackjump is achieved with a shorter rotation waiting time. A rotationwaiting time occurs when, for example, a track jump occurs but the nextpicture to be reproduced is not located under the optical head 8. Thus,one must wait for the disc 12 to rotate such that the next picture to bereproduced is properly located under the optical head 8. In the drawing,reference numeral 69 denotes an audio header indicating the head of theaudio signal, 70 denotes audio data, 71 denotes a video data recognitionparity for recognition of the head of the video data, 72 denotesP2-picture header indicating the head of the second P-picture, 73denotes P2-picture data, 74 denotes a B-picture header indicating thehead of B-pictures, 75 to 79 denote B1- to Bn-picture data, and 80denotes an end mark indicating the end of the GOP.

[0170] In FIG. 9, the positions at which I- and P-picture imageinformation is disposed are shifted from one GOP to anothertrack-adjacent GOP, so that I-picture reproduction at the time of trackjump is achieved with an even shorter rotation waiting time. In thedrawing, reference numerals 81 to 88 denote B-picture (B5- toB12-picture) data.

[0171] The operation of Embodiment 2 will next be described withreference to the drawings. In FIG. 7A, the data in the GOP is arrangedin the order of I-, P- and B-pictures. In this case, special playback isachieved by repeating the steps of reading the video header 52 includingthe video GOP address 49 and the video attribute data 50 shown in FIG.2A, then reproducing an I-picture, and skipping P- and B-pictures, andthen reproducing an I-picture in the next GOP, and so on.

[0172] In such a case, because the data occupation proportion of anI-picture in each GOP is fairly large, and the amount of data of anI-picture is three to five times the amount of data of a B-picture.Therefore, even if reproduction of P- and B-pictures is omitted, thespecial playback efficiency (as a ratio of the amount of data which isnot read to the amount of data that is read during special playback) isnot so high, and in addition the rotation waiting time is present. As aresult, the special playback speed multiplier is not high. If, however,one GOP consists of 10 pictures as shown in FIG. 32 or 15 pictures asshown in FIG. 33, special playback at about double or triple speed ispossible.

[0173] In order to reduce the rotation waiting time, the dataarrangement shown in FIG. 8 is conceived. In the illustrated dataarrangement, the order of I- and P-pictures is opposite betweentrack-adjacent GOPs. In the case of FIG. 8, when reproduction of anI-picture 53 in a first GOP is completed, and track jump is effected,then reproduction of an I-picture 53 in the next track-adjacent GOP iscommenced immediately or after only a certain servo stabilizing period.

[0174] Furthermore, by changing the order of the I-, P- and B-picturesevery track-adjacent GOP as shown in FIG. 9, it is possible to achievean arrangement in which I-pictures can be read continuously for moreGOPs. In the illustrated example, I-pictures can be read continuouslyfor three GOPs, so that substantially smooth special playback by thecontinuous reproduction of I-pictures for the three GOPs is possible.

[0175] By reproducing I-picture data, playback can be achieved withoutrotation waiting between GOPs. Accordingly, unlike Embodiment 1, smoothcontinuous motion picture special playback is possible.

[0176] Embodiment 3

[0177]FIG. 10 shows a format arrangement on a disk of a continuousgroove type in Embodiment 3. FIG. 11 shows a format arrangement on adisk of a sample servo type in Embodiment 3. FIG. 12 is a flowchartshowing the operation of reading data in which the disk rotation speedis increased during special playback.

[0178] The operation of Embodiment 3 will next be described. Generally,for the purpose of increasing the recording density of an optical disk,constant linear velocity (CLV) recording is advantageous over constantangular velocity (CAV) recording. However, in CLV recording, the head ofimage data and the disposition on the I-picture on the disk is notfixed, and because in particular the angular position of the I-picturesis at random, the operation of Embodiment 1 or Embodiment 2 isdifficult. The disk is therefore divided into zones, e.g., zones A to Fas illustrated in FIG. 10 or FIG. 11, and the head regions of the GOPswithin each zone are made to be aligned in the radial direction of thedisk.

[0179] The linear recording density can be made substantially equalbetween different zones, by varying the disk motor rotational speedbetween different zones, or by varying the frequency of the data clockduring recording and playback.

[0180] But in such a case, the recording capacity per one revolution ofthe disk is different between different zones. It is possible to realizethe zone division by which the recording capacity per GOP is a multipleof the recording capacity per revolution. For instance, it may be so setthat one GOP is formed of five tracks in the innermost zone, while oneGOP is formed of two tracks in the outermost zone.

[0181] Instead of setting the recording capacity per GOP to be amultiple of the recording capacity per revolution, it may alternativelybe so set that the recording capacity per GOP is a multiple of therecording capacity per half a revolution. Then, finer zone division ispossible. If it is so set that the recording capacity per GOP is amultiple of the recording capacity per a quarter of one revolution, evenfiner zone division is possible.

[0182] In this case, the GOP address in the video information is writtenimmediately after the servo pits (wobble pits) in the sample servo typeor the mirror surface part in the continuous guide groove type, and bysetting the length of the mirror surface part or the wobble pits inwhich the GOP address is recorded to be of a different length from otherparts, the sum signal (reflection signal) from the optical head can beused as an index during search.

[0183] In the system for recording and playing back digital motionpicture image using an optical disk, such as those described above, thespecial playback can be achieved by using track jump as described inconnection with Embodiment 1 and Embodiment 2. It is also possible toincrease the disk rotation speed during continuous playback in order tofurther increase the overall playback speed. For instance, the diskrotation speed is doubled, and the data transfer rate is doubled, andyet the data reproduction is possible. By reproducing I- and P-picturesonly, double speed playback can be achieved.

[0184] If the disk rotational speed is increased to four or eight times,the data rate is too high, and the data detection may be impossible. Insuch a case, while I- and P-pictures are reproduced the disk rotationalspeed may be lowered to such a value at which playback is possible, andwhile B-pictures are reproduced the disk rotation speed may beincreased, as shown in FIG. 3B.

[0185] The operation of the optical disk drive for such a playback is asshown in FIG. 12. The operation including the following steps isrepeated. First, the rotational speed is increased to n-times, and thenthe video header is detected to read an I-picture, and jump is made tothe next GOP. By disposing an I-picture in the video attribute data 50,the disk motor acceleration region and the deceleration region can beset. Embodiment 4

[0186] Embodiment 4 of the invention will next be described. FIG. 13Aand FIG. 13B show the data structure of the digital motion picture imageaccording to Embodiment 4. FIG. 13A shows the structure of a GOP, FIG.13B shows the data arrangement of the entire GOP including audio data.In the drawings, reference numerals 21 to 29 denote data identical tothose described in connection with the prior art example with referenceto FIG. 30 to FIG. 33. Reference numeral 130 denotes a header indicatingthe head of the data, 131 denotes an address of each GOP forming a unitof editing, 132 denotes attribute data attendant to the digital motionpicture image data, 133 denotes an audio header indicating the head ofaudio data 134. Reference numeral 135 denotes a video header indicatingthe head of video data 136. Reference numeral 137 denotes a P-pictureheader indicating the head of a P-picture 29. Reference numeral 138denotes a B-picture header indicating the head of a B-picture 28. In thedrawings, P-, B- and I-pictures are respectively represented as“P-picture,” “B-picture,” and “I-picture.”

[0187]FIG. 14 shows the details of configuration of the digital motionpicture image data arrangement in Embodiment 4 Reference numeral 139denotes wobble pits in the sample format or a mirror surface part foroffset correction in the continuous guide groove type, 140 denotes azone address in the optical disk of a zone constant angular velocity(CAV) rotation system, 141 denotes a sector address for each sectorwhich is a fraction of a GOP, 142 denotes a video GOP address for eachvideo GOP, 143 denotes a video attribute data attendant to a digitalmotion picture image, and 145 denotes an I-picture header indicating thehead of I-picture data 146. Reference numeral 147 denotes I-picture ECC(error correction code) recording the I-picture data error correctioncode, and 148 denotes a P-picture header indicating the head ofP-picture data 149. Reference numeral 150 denotes a scalability mode,151 denotes the number of frames within the GOP, 152 denotes the GOPstructure showing the arrangement of I-, B- and P-pictures, and the likewithin the GOP, 153 denotes the arrangement and position of data withinan I-picture, 154 denotes detailed attribute data such as presence orabsence of panning, zooming and scene change, 155 denotes a time code,156 denotes an address of destination of jump during special playback,157 denotes an audio mode, 158 denotes a still picture mode, and 159denotes a spare area.

[0188]FIG. 15 is a block diagram showing an optical disk recordingdevice for use with an optical disk according to Embodiment 4. Theillustrated recording and playback device is identical to that shown inFIG. 1, except that the scene change detector 100 in FIG. 1 is notprovided. The reference numerals 8, 10-12, 30-39, and 43 to 46 denotemembers or components identical to those in FIG. 1.

[0189]FIG. 16 shows the structure of details of the part where I-picturedata is recorded on the optical disk. The video header 135 indicates thehead of the video data in nth track group, 160 denotes fraction dataformed of a plurality of slices for the top ⅓ part (from the top edge toa first horizontal dividing line ⅓ as measured from the top edge of thescreen) of the screen of the I-picture 27. Reference numeral 162 denotesa fraction data formed of a plurality of slices for the middle ⅓ part(from the first horizontal division line to a second horizontal dividingline at ⅔ as measured from the top edge of the screen) of the I-picture27. Reference numeral 164 denotes a fraction data formed of a pluralityof slices for the bottom ⅓ part (from the second horizontal dividingline to the bottom edge of the screen) of the I-picture 27. Referencenumeral 161 denotes a sub-header indicating the head of fraction data162. Reference numeral 163 denotes a sub-header indicating the head isof fraction data 164. Reference numeral 148 denotes a P-picture header,165 denotes a first P-picture data within the GOP, and 166 denotes aheader indicating the head of a second P-picture data 167. Referencenumeral 168 denotes a header indicating the entirety of each of thedigital motion picture image of (n+1)-th and (n+2)-th track groups, andalso indicating the head of P-picture data, 169 denotes a headerindicating the part 160 where the data for the slices 23 in the upper ⅓part of the screen of the I-picture 27 is recorded.

[0190]FIG. 17 is a flowchart showing the operation of special playbackof a motion picture in an optical disk device, with a system having adigital motion picture image data file structure in which the screen isdivided in the vertical direction of the screen into fractions, eachcomprising a multiple of slices.

[0191] The operation will next be described. A digital motion pictureimage data usually is formed of a mixture of data of I-, B- andP-pictures 27, 28 and 29, as shown in FIG. 31 to FIG. 33 in connectionwith the prior art example. An I-picture 27 can be reproducedindependently because two-dimensional compression is used. However,P-pictures cannot be reproduced until the I-picture is reproduced, andB-pictures cannot be reproduced until the I- and P-pictures have beenreproduced. A data arrangement on the disk that is advantageous from theview point of the signal processing is therefore, that I and P-picturesare successively disposed first in the GOP as shown in FIG. 13B, andB-pictures are thereafter disposed.

[0192] In this case, it is also desirable that the audio data is alsoarranged for each GOP. This enables after-recording (recording audiosignal after video signal) and editing. Moreover, with the datastructure shown in FIG. 13A and FIG. 13B by providing video GOP address142, headers 145 and 148 indicating the heads of I- and P-pictures asshown in FIG. 14, to enable editing for each GOP it is possible toextract a I-picture data of a single picture alone, or P-picture data ofa single picture alone.

[0193] By providing a region 143 in which attribute data of the digitalmotion picture image data is written, and by providing scalability mode150 indicating whether the hierarchial structure is suitable for usewith the particular numbers of pixels and lines on the screen, thenumber of frames, 151, within the GOP, the GOP structure 152 indicatingthe arrangement and the like of I-, B- and P-picture data within theGOP, the disk can be used in conjunction with a variety of signalprocessing systems. By describing the I-picture data structure withinthe GOP structure 152, the arrangement suitable for the special playbackwhich will be described below can also be adopted.

[0194] As has been described, with the format in which I- and P-picturesare successively disposed in the GOP, it is possible to implementspecial playback by modifying the I-picture data structure. In thiscase, by dividing the I-picture data into one-third fractions, eachcomprising an integer number of slices, as shown in FIG. 16, and thepositions of the file blocks corresponding to the respective positionson the screen are exchanged between GOPs. Such a data arrangement ispossible by controlling the buffer memory 38 by means of the formatencoder 39 in the optical disk recording and playback device shown inFIG. 15.

[0195] With the file structure shown in FIG. 16, if the heads of theGOPs are aligned in the disk radial direction, it is possible toreproduce image of one picture from 3 GOPS, by performing track jumps,as illustrated, and adjoining the data for the fractions of I-picture.Partial continuous reproduction of I-pictures can be achieved with shortrotation waiting times, so that the speed of the fast playback usingI-picture data can be made high even though the amount of I-picture datais larger than P- and B-pictures.

[0196] Moreover, with the disk format of the zone CAV system, GOP headdata can be aligned in the disk radial direction, if the zone allocationis such that the amount of data per GOP is a multiple of one revolutionor a multiple of half a revolution.

[0197] The operation of the optical disk device during the specialplayback described above is shown in the flow chart of FIG. 17. First,when the special playback is started, the video GOP address is detected,and the time code and the like are displayed on the screen by means of acharacter generator or the like. Next, the video attribute data in theGOP is read, and judgment as to whether the I-picture is of the dividedtype. If it is of the divided type, the header at the top part of thescreen of an I-picture is detected, and the data is read, and track jumpis then performed, and the header for the central part of the screen isdetected and the data is read, and jump is again made, and the headerfor the bottom part of the screen is detected and the data is read. Thefractional data of the I-picture are adjoined by the image memory(buffer memory 38 in FIG. 15). The above operations are repeated untilthe special playback is completed. In this way, fast playback andreverse playback can be achieved.

[0198] By application of the invention, the special playback speedmultiplier can be improved even in the case of an optical disk of a CLVsystem. This is because the data of the I-pictures is divided andfractions thereof are reproduced, while in the prior art all theI-picture data were reproduced. Note in this connection that the datacapacity of an I-picture is much larger than the B- and P-pictures, andduring special playback, an I-picture and then P-pictures arereproduced, or only I-pictures are reproduced successively.

[0199] Embodiment 5

[0200]FIG. 18A shows the arrangement structure of the digital motionpicture image data in Embodiment 5. Reference numerals 171 to 177 denotenew file blocks which are formed when the block layer 26 is of a digitalmotion picture image in DCT encoding is divided with reference to thespatial frequency as shown in FIG. 18B In FIG. 18A and FIG. 18B, thefile structure within an I-picture for each GOP is divided into groupsof respective spatial frequency regions in DCT codes, and thedisposition is altered from one GOP to another. The frequency of therespective groups is increased in the order of (a) to (g).

[0201]FIG. 19 shows a data structure which is a modification of FIG.18A. The arrangement of I- and P-picture data is altered from one GOP toanother. In the drawing, reference numeral 180 denotes an I-pictureheader indicating the head of the I-picture data.

[0202]FIG. 20 shows an example in which each GOP has four P-pictures.Reference numeral 181 denotes a third P-picture header indicating thehead of third P-picture data 178, and 182 denotes a fourth P-pictureheader indicating the head of fourth P-picture data 179.

[0203]FIG. 21 shows the operation of special playback taking account ofthe rotation waiting with the digital motion picture image dataarrangement shown in FIG. 20. FIG. 22 is a flowchart showing theoperation of the optical disk drive for the case where I-picture data isdivided according to the frequency.

[0204]FIG. 23 shows the data arrangement on the optical disk for thecase where the optical disk of a zone CAV system is formatted accordingthe sample servo system. In the drawing, reference numeral 223 denotes aheader and servo pits, 224 denotes a sector address, 225 denotes audiodata, 226 denotes a sub-header for the data block (d) to (g) in theI-picture, 227 denotes I-picture data for the (d) to (g) of theI-picture, and 228 denotes a header for the audio data

[0205]FIG. 24 shows the data arrangement on the optical disk for thecontinuous guide groove system. In the drawing, reference numeral 229shows a mirror surface part for detecting the offset of the trackingsensor during tracking in the push-pull method, and 230 denotes are-sync byte for the case where a modulation system having anintermittent data structure of the 2-7 modulation or 1-7 modulation isused. The re-sync byte contains a reference clock for PLL for thepurpose of data detection.

[0206] The operation of Embodiment 5 will next be described. In thestandard digital motion picture image compression system represented byMPEG, JPEG, and the like, the data arrangement is obtained throughdivision according to the vertical and horizontal spatial frequencies atthe time of DCT encoding of each macroblock 24, and scanning in zig-zagfashion as shown in FIG. 18B. For instance, if the 64 DCT encoding dataof I-picture data are divided into blocks, seven blocks (a) to (g), eachconsisting of 9 or 10 DCT encoding data are formed. At the time of datarecording, these I-picture data are not arranged taking each slice 23 asa unit, but are arranged taking each of the blocks (a) to (g) as a unit,as illustrated, and a header signal, a parity signal, and the like areadded to the head of the block forming each of fractions generated bythe division according to the frequency regions, it is possible toobtain image during special playback, by reproducing the data closer tothe DC component of the DCT encoding data. In this way, it is notnecessary to reproduce the entirety of each I-picture data having arelatively large data amount.

[0207] Assume, for instance, that the optical disk has the structure ofthe zone CAV system, and the GOP head positions are aligned in the diskradial direction. By re-arranging the data blocks (a) to (g) of anI-picture for each GOP as shown in FIG. 18A, it is possible tocontinuously reproduce only data block (a) in the I-picture data.

[0208] If, for instance, a signal of a rate four times that of thecurrent standard CD (compact disk) were recorded at a double lineardensity on an optical disk of the current CD size (the diameter being 15cm), the disk rotation speed would be changed from 600 rpm to 1200 rpm,and the worst rotation waiting time would be the time corresponding tothree pictures.

[0209] For this reason, where one GOP is formed of 15 pictures, and ifan I-picture can be read within a time for one picture (about 33 msec),it is possible to perform a 15-time speed playback in which I-picturesare successively reproduced. If a rotation waiting occurs, the timecorresponding to three pictures (about 100 msec.) is wasted perrevolution, and the maximum playback speed will be five time the normalspeed.

[0210] If a playback system in which a next GOP is skipped and anI-picture in the next-but-one GOP is reproduced is employed, to preventthe degradation in the special playback speed multiplier, one out of 30pictures is displayed, and at the time of 15-time speed, the samepicture is displayed twice. The motion in the displayed motion pictureis awkward. Moreover, a necessary scene may be missed as the skipping isincreased.

[0211] To prevent the awkwardness and skipping, the amount of reproduceddata of the I-picture is reduced to the extent in which imagerecognition is possible. That is, only the low-frequency components inthe DCT encoding are reproduced, for example. Moreover, position of thelow-frequency component is altered from one GOP to another. In addition,track jump is repeated. By these measures, the rotation waiting time isshortened.

[0212] Furthermore, if digital motion picture image data is recorded asshown in FIG. 19, instead of successively reproducing only the datablock (a) of an I-picture data as shown in FIG. 18A, data blocks (b) and(c) of the I-picture data are also reproduced, with the result thatfiner image can be reproduced even in special playback. If the positionsof the I- and P-pictures are exchanged, in addition to the exchange ofthe positions of the data blocks (a) to (c) within the I-picture data asshown in FIG. 19, the rotation waiting time in special playback isfurther reduced. In this case, every four GOPs form a group for whichcontinuous data is obtained, and the fast playback is achieved by asuccession of such groups each consisting of four GOPs.

[0213] Furthermore, if the number of P-pictures per GOP is four as shownin FIG. 20, every two P-pictures are made to form a group, and thepositions of each group and an I-picture are exchanged to achieve fastplayback in which data blocks (a) to (c) of an I-picture data arereproduced. In this case, every six GOPs form a group for whichcontinuous data is obtained, and the fast playback is achieved by asuccession of such groups each consisting of six GOPs.

[0214] Where a certain rotation waiting is permitted, and if specialplayback is at a several-time speed, track jump as shown in FIG. 21 isperformed. If track jump is performed as indicated by dotted line,reproduction of I-pictures is affected every alternate GOPs (using datablocks (a) to (g) of every second GOP), while if track jump is performedas indicated by a solid line, reproduction of I-pictures is effectedevery GOP (using data blocks (a) to (c) of every GOP).

[0215] As the data arrangement within I-pictures is altered as shown inFIG. 21, the operation as indicated by the solid line is possible, andfiner movement can be realized than in the case of the dotted line.

[0216] During the special playback as described above, the optical diskdrive performs the operation as shown in the flowchart of FIG. 22.First, the address of the head of the GOP of the digital motion pictureimage data is detected, and the time information such as time code, diskaddress information, or the like is displayed on the screen. Then, videoattribute data is read, and judgement is made as to whether theI-picture data is frequency-divided. If it is frequency-divided, thehead of the low-frequency component of the I-picture is detected, andthe I-picture low-frequency component is read, and a correspondingpicture is displayed, and track jump over a predetermined number tracksis performed. The above operations are repeated until the completion ofthe special playback. In this way, the data of the low-frequencycomponents in the DCT encoding of I-pictures is sequentially reproduced,and special playback is achieved in this way.

[0217] In an optical disk having a disk format of a sample servo system,if sectors, each formed of a part from a header and servo pits 223 tothe next header and servo pits 223, as shown in FIG. 23, are aligned ina radial direction within each zone, and I-picture data, P-picture data,audio data and the like are completed over a multiple of sectors of saidsample servo format, the disk structure shown in FIG. 18A to FIG. 21 isrealized on the disk.

[0218] In an optical disk having a disk format of a continuous guidegroove system, it is possible to adopt a file structure on the disk asshown in FIG. 24 to provide similar effects, i.e., to realize the diskstructure shown in FIG. 18A to FIG. 21. In this case, a part from onemirror surface part 229 to another mirror surface part 229 form a largefile unit. This large file unit can be sub-divided by re-sync byte 230into sub-division file units, and I-picture data, P-picture data, audiodata and the like are made to be of such a length which is a multiple ofthe sub-division file units. In this way, it is possible to realize thedata structure on the disk as shown in FIG. 18A to FIG. 21.

[0219] Description has been made for the case where the optical disk isof a zone CAV format. In the case of CLV format as well, it is possibleto improve the special playback speed multiplier by frequency-dividingthe I-pictures.

[0220] Embodiment 6

[0221] Embodiment 6 of the invention will next be described.

[0222]FIG. 25 is a block diagram showing a decode circuit for restoringthe image signal of 780 pixels×480 lines from a layered information, thelayered information being obtained by layering digital motion picturecompressed image information into compressed information correspondingto 780 pixels×480 lines, and compressed information corresponding to 360pixels×240 lines. In the drawing, reference numeral 201 denotes avariable-length encoder, 202 denotes an inverse quantizer, 203 denotesan inverse discrete cosine transform circuit, 204 denotes a motioncompensating circuit, 205 denotes a frame memory, and 206 denotes adecoder for restoring the digital motion picture compressed image dataof the lower layer.

[0223]FIG. 26 is a block diagram showing an optical disk device fordecoding the digital motion picture compressed image informationrecorded on the optical disk, being layered, using the decode circuitshown in FIG. 25. In the drawing, reference numeral 207 denotes aplayback amplifier for reproducing digital motion picture imageinformation recorded on the optical disk, and 208 denotes adata-detection & PLL circuit for detecting the data from the signal fromthe playback amplifier 207. Reference numeral 209 denotes a headerdetection & data discriminating circuit for detecting the header signalin the data detected by the data detection & PLL circuit 208 anddiscriminating the data. Reference numeral 210 denotes an errorcorrection circuit.

[0224]FIG. 27 is a diagram showing the disposition of layered I- andP-picture data on the disk. Reference numeral 211 denotes a lower-layerdata of an I-picture corresponding to digital motion picture imageinformation of 360 pixels×240 lines, 212 denotes an upper-layer data ofthe I-picture which, in combination with the lower-layer data 211, formdata of 780 pixels×480 lines, and 213 denotes a header of the upperlayer data 212. Reference numeral 214 denotes a lower-layer data of aP-picture, 215 denotes an upper-layer data of the P-picture, 217 denotesa lower-layer data of a second P-picture, 218 denotes an upper-layerdata of the second P-picture, 219 denotes denotes a header of theupper-layer data of the second P-picture, 220 denotes a header of theupper-layer data of the I-picture, 221 denotes a header of theupper-layer data of the first P-picture, and 222 denotes a header of thelower-layer data of the second P-picture.

[0225]FIG. 28 shows the arrangement, on the disk, of data of which onlyI-picture data is layered.

[0226] The operation of Embodiment 6 will next be described

[0227] In the MPEG system is now established as an internationalstandard, there is a method in which the data structure is layered, anddivided into a lower-layer image data of 360 pixels×240 lines, andupper-layer image data which, in combination with the lower-layer imagedata, form data of 780 pixels×480 lines. The upper-layer data and thelower-layer data are combined at the decode circuit shown in FIG. 25 toform a synthetic picture of 780 pixels×480 lines which is a digitalmotion picture image information of the upper layer.

[0228] Where the I- and P-pictures are layered, the data may be arrangedon the disk as shown in FIG. 27. The upper-layer and lower-layer data ofthe I- and P-pictures are disposed, being separated by headers and thelike, and the positions of the I- and P-pictures are altered from oneGOP to another. In this way, at the time of special playback, track jumpis performed, and only the lower-layer data of the I-picture iscontinuously read.

[0229] Moreover, it is also possible to layer the I-pictures only, tothereby simplify the configuration. In this case as well, the positionsof the I-picture data and P-picture data may be altered from one GOP toanother, to enable continuous reading of the I-picture lower-layer data.Generally, the amount of I-picture data occupies a larger area in theGOP, so that if it is attempted to read all the data, the speedmultiplier of the special playback cannot be made high. By reading onlythe lower-layer data of I- and P-pictures, the special playback speedmultiplier can be made high, and the number of frames forming thespecial playback picture can be increased so as to make the motionsmooth.

[0230]FIG. 26 is a block diagram showing the optical disk recording andplaying back device which can restore layered data. The playback signalfrom the optical disk that has been amplified by the playback amplifier207 is detected as data by the data detector 208, and divided into theupper-layer data and lower-layer data at the header detector/datadiscriminator 209. The discriminated data is error-corrected at theerror correction circuit 210, and input into a layered-data decodecircuit similar to that shown in FIG. 25, to achieve reproduction ofimage. With the lower-layer data alone, only the image of 360 pixels×240lines can be obtained.

[0231] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included with the scope of the following claims.

In the claims:
 1. An optical disk recording digital image information inthe form of a succession of image information blocks, each comprisingI-picture data of an I-picture obtained by intra-frame encoding,P-picture data of one or more P-pictures obtained by encoding withforward motion compensation, and B-picture data of B-pictures obtainedby encoding with motion compensation using the data of the I- and/orP-pictures positioned in front and at the back thereof as referencepictures, wherein an address data preformatted in front of therespective image information blocks (or image files) are aligned on astraight line extending in the radial direction to reduce rotationwaiting time upon a track-jump event.
 2. An optical disk recordingdigital image in information in the form of a succession of imageinformation blocks, each comprising I-picture data of an I-pictureobtained by intra-frame encoding, P-picture data of one or moreP-pictures obtained by encoding with forward motion compensation, andB-picture data of B-pictures obtained by encoding with motioncompensation using the data of the I- and/or P-pictures positioned infront and at the back thereof as references pictures, whereinpresence/absence of scene change detected from the temporal change inthe luminance or chrominance information of the image is recorded in anattribute data recording area at the head of each of the imageinformation blocks.
 3. A method of playing back an optical disc whereinthe rotational speed of the optical disk during fast playback or reverseplayback or motion picture image is higher than the rotational speed ofthe optical disk during normal playback.
 4. A method of playing back anoptical disk wherein the rotational speed of the optical disk is raisedfor a region in which no data needs to be read during fast forward orreverse playback of a motion picture image recorded on the optical disk,and is lowered to the linear velocity at which reproduction of data ispossible, for a region in which I- and P-picture data is recorded.
 5. Anoptical disk recording digital image information in the form of asuccession of image information blocks, each comprising I-picture dataof an I-picture obtained by intra-frame encoding, P-picture data of oneor more P-pictures obtained by encoding with forward motioncompensation, and B-picture data of B-pictures obtained by encoding withmotion compensation using the data of the I- and/or P-pictures positionin front and at the back thereof as reference pictures, wherein saidI-picture data is divided into fractional I-picture data for a pluralityof regions into which a display screen is divided, wherein eachfractional I-picture data includes a plurality of slices; and whereinthe fractional I-picture data are arranged in said image informationblock, and a header or parity signal is recorded in front of eachfractional I-picture data.
 6. The optical disk according to claim 5,wherein the order of data arrangement of I-, P-, and B-picture datawithin an image information block is different at least betweentrack-adjacent image information blocks.
 7. The optical disk accordingto claim 5, wherein identification signal indicating whether theI-picture data is a screen-divided data, a frequency-divided data, ordata divided by the numbers of pixels and lines is written at the headof each image information block.
 8. The optical disk according to claim5, wherein the head positions of the digital image information blocksare aligned in the radial direction of the optical disk.
 9. A method ofplaying back from the optical disk of claim 5 comprising the steps of:using an optical disk playback device including a tacking actuator fortracking a scanning spot on a predefined track, a tracking controlcircuit, and a track jump circuit for performing jumping scanning, andrepeating jumping operation on the basis of a header or parity signalrecorded in front of each I-picture data to perform high-speed forwardor reverse playback.
 10. An optical disk in which encoded I-picture datais divided into a plurality of sub-blocks wherein each I-picturesub-block is allocated encoded I-picture data according to thehorizontal and vertical frequencies, from a DC component to thehigh-frequency components, track-adjacent I-picture sub-blocks in thetrack-adjacent image information blocks in the adjacent tracks aredisposed with their order being altered, and a header or parity signalindicating which of the frequency components the content of eachsub-block is for is recorded in front of each sub block.
 11. The opticaldisk according to claim 10, which encoded I-picture data is allocatedinto a plurality of sub-blocks according to the horizontal and verticalfrequencies, from the DC components to the high-frequency components,the frequency-divided I-picture data within the adjacent imageinformation blocks in the adjacent tracks are disposed differently, andheader or parity signal indicating which of the frequency components thecontent of each sub-block is for is recorded in front of each sub-block.12. The optical disk according to claim 10, wherein the order of dataarrangement of I-, P- and B-picture data within an image informationblock is different at least between track-adjacent image informationblocks.
 13. The optical disk according to claim 10, whereinidentification signal indicating whether the I-picture data is ascreen-divided data, a frequency-divided data, or data divided by thenumbers of pixels and lines is written at the head of each imageinformation block.
 14. The optical disk according to claim 10, whereinthe head positions of the digital image information blocks are alignedin the radial direction of the optical disk.
 15. A method of playingback from the optical disk according to claim 10, comprising the stepsof: using an optical disk playback device comprising a tracking actuatorfor tracking a scanning spot on a predefined track, a tracking controlcircuit, and a track jump circuit for performing jumping scanning, andrepeating jumping operation on the basis of a header or parity signalrecorded in front of each I-picture data to perform high-speed forwardor reverse playback.
 16. An optical disk storing digital imageinformation in the form of a succession of blocks, each comprising aplurality of frames comprising, in mixture, I-picture data forming imageinformation obtained by intra-frames encoding, P-picture data obtainedby encoding with forward motion compensation, and B-picture dataobtained by encoding with motion compensation using said I- and/orP-picture data positioned in front and at the back thereof asreferences, wherein the digital motion picture image information isdivided into lower-layer data and upper-layer data wherein an imageobtained by the lower-layer data alone has a resolution lower than aresolution of image data obtained from the combination of theupper-layer data and the lower-layer data, and wherein a header orparity signal for indicating the type of the data block is recorded infront of each data block, wherein the order of data arrangement of I-,P- and B-picture data within an image information block is different atleast between track-adjacent image information blocks.
 17. The opticaldisk according to claim 16, wherein identification signal indictingwhether the I-picture data is a screen-divided data, a frequency-divideddata, or data divided by the numbers of pixels and lines is written atthe head of each image information block.
 18. A method of playing backfrom the optical disk of claim 17, comprising the steps of: using anoptical disk playback device comprising a tracking actuator for trackinga scanning spot on a predefined track, a tracking control circuit, and atrack jump circuit for performing jumping scanning, and repeatingjumping operation on the basis of an identification signal written atthe head of each image information block to perform high-speed forwardor reverse playback
 19. The optical disk according to claim 16, whereinthe head positions of the digital image information blocks are alignedin the radial direction of the optical disk.
 20. A method of playingback from the optical disk according to claim 16 comprising the stepsof: using an optical disk playback device comprising a tracking actuatorfor tracking a scanning spot on a predefined track, a tracking controlcircuit, and a track jump circuit for performing jumping scanning, andrepeating jumping operation on the basis of a header or parity signalrecorded in front of each I-picture data to perform high-speed forwardor reverse playback.